GEAR CUTTING ON STANDARD MACHINES

The history of Kumera Antriebstechnik GmbH from Graz dates back to the year 1898, when Norricum Cless Graz built chainless gears for bicycles. Since 2000 the company has been a wholly owned subsidiary of the Finnish Kumera Cooperation. Within the Kumera Power Transmission Group, the Austrian company with its approximately 50 employees produces special gear units for hydropower plants, the paper industry and chemical installations. 50 percent of sales are also generated by the service business, such as the overhaul and repair of industrial gearboxes from our own product range as well as third-party products. Reliable machining of the gear components is ensured by five turning and turn-mill machines from DMG MORI, including an NT 5400 and the NT 6600 installed in 2021 for turned parts having diameters of up to ø 1,070 mm and lengths up to 4,000 mm. Kumera produces sophisticated gears on both turnmill centers with the help of the exclusive DMG MORI gearMILL technology cycle.

Thanks to the gearMILL software,
we can produce almost any gear shape with standard tools on our turn-mill machines – to a quality comparable to special gear cutting machines.

Helmut Hochegger
Managing Director
Kumera Antriebstechnik GmbH

NT6600 DCG: TURN-MILL MACHINING OF WORKPIECES UP TO ø 1,070 × 4,000 mm

Reverse engineering of individual parts in just a few days

“The order situation has developed positively over the past few years,” says Helmut Hochegger, Managing Director of Kumera Antriebstechnik, about the good utilization of capacity in production. As the focus is mainly on individual parts that have to be delivered as quickly as possible, flexibility plays a key role. “Especially in the service business, we try to provide spare parts within a few days.”The engineering expertise of the team is an important mainstay in this sector.“Very often we only have a single component, which we measure completely, redesign and carry out calculations and then produce it in the required quality”, is how Helmut Hochegger describes the reverse engineering process.

In production, Kumera can draw on a number of different technologies: conventional machining, wire eroding, hobbing and grinding. The company continuously optimizes its processes by regularly investing in innovative manufacturing solutions. “The two turnmill centers from DMG MORI helped us enormously here”, says Helmut Hochegger recalling the procurements. With their large work areas, both the NT 5400 and the NT 6600 cover a wide range of components and offer maximum machining versatility. Long shafts, for example, can be set up thanks to the steady rest.

Turned parts having diameters of up to ø 1,070 mm and 4,000 mm long can be produced on the NT 6600. Long shafts can also be set up easily thanks to the steady rest.

Maximum reliability – in use for over 20 years

Helmut Hochegger has been familiar with the high level of reliability of the DMG MORI models for many years: “We already had lathes from Japan in use in the 1990s and still use some of them today for training purposes.” The quality is impressive after such a long time. “The sturdy construction ensures optimum long-term accuracy and a high level of process reliability.”

Fast and simple gear production with gearMILL

The main reason for the purchase of the NT 5400 was the possibility of milling gears efficiently. What DMG MORI had previously made possible on machining centers and CTX TC models was implemented on an NT machine for the first time. “With the gearMILL technology cycle, we can produce herringbone, bevel and helical gears at any time – quickly and with maximum precision,” says Helmut Hochegger, assessing the technology integration. “Depending on the size, we achieve quality in the range DIN 5 to 7.” After the successful introduction of gearMILL on the NT 5400, it was clear that Kumera would implement the same principle on the larger NT 6600 in 2021.

NT6600 DCG：TURN & MILL WORKPIECES OF LARGE DIAMETER

• Workpieces up to ø1,070 ×6,076 mm
• 6-sided complete machining thanks to the main and optional right spindle
• 660 mm Y-axis for eccentric machining
• Turn-mill spindle with up to 8,000 rpm and 302 Nm
• Tool magazine for up to 140 tools^*
• Boring bar with a length of 1,270 mm for Capto C8 tools

* Option

Cost-efficient production of demanding gears

What makes gearMILL so easy to use is the program creation based on drawings and gear data. In the case of the two NT machines, production takes place on standard machines with standard tools. “In combination with user-friendly programming, this allows us to produce sophisticated gears flexibly and economically,” explains Helmut Hochegger.

Healthy growth and motivation of the next generation

Kumera remains competitive in a fiercely contested market by investing in advanced manufacturing solutions, such as the complete machining of gears described above. Added to this are investments in training and further education, as Helmut Hochegger goes on to tell us: “Well-trained specialists are needed to get the most out of the technology.” In addition Kumera promotes a self-reliant way of working in its modern production facility. “Experience shows that this contributes to staff motivation.”

Into the future with technology integration and complete machining

Technological progress in production will continue to play a major role at Kumera in the future. Also, against the background of limited production space at the urban site, complete machining and technology integration are a great help, says Helmut Hochegger: “We focus on high-quality products and components, which we must manufacture all the more efficiently if we want to keep growing strongly.”

TECHNOLOGY CYCLE gearMILL

GEAR CUTTING ON STANDARD MACHINES WITH STANDARD TOOLS

• Program creation based on drawings and gear data
• Individually modifiable contact pattern
• Post-processor for SIEMENS, HEIDENHAIN and MAPPS
• Interface for coordinate measuring equipment (Klingelnberg, Leitz, Zeiss)
• SPUR GEARS: Spur, helical and herringbone gears, segments
• BEVEL GEARS: Spur, helical, spiral bevel and hypoid gears, axis angles other than 90°, Klingelnberg Zyklo-Palloid and Gleason
• WORM WHEELS: Profile ZA, ZN and ZI

Note: Organization names and titles are current as of publication timing.